ROCHESTER (AP) >> A woman charged with buying guns for a convicted felon who later used them to kill two volunteer firefighters in an ambush was convicted Tuesday of falsifying business records.

A state Supreme Court jury in Rochester found 25-year-old Dawn Nguyen, of the town of Greece, guilty because she lied when she said on a gun purchase form that she was buying the weapons for her own use. She also faces federal charges.

Prosecutors say Nguyen bought a semi-automatic rifle and a 12-gauge shotgun at a Gander Mountain store in 2010 for her neighbor William Spengler Jr., who was prohibited from owning weapon because of his felony record. Spengler had been released from prison in 1996 after serving 17 years for killing his grandmother with a hammer.

Spengler set fire to his Webster home early on the morning of Dec. 24, 2012, then shot at responding firefighters, killing Michael Chiapperini and Tomasz Kaczowka and wounding Joseph Hofstetter and Ted Scardino. Spengler then committed suicide.

Prosecutor Timothy Prosperi said Nguyen’s bail was revoked after the verdict on Tuesday and she was sent to the Monroe County Jail to await sentencing on May 19. He said she faces a maximum of 1 1/3 to four years in state prison.